Blower motor operation for an electrified vehicle

ABSTRACT

A method of operating a vehicle climate system includes, by a controller, responsive to a same blower motor request, operating a blower motor at a first speed responsive to a heater core isolation valve (HCIV) directing coolant used to heat a cabin to an engine. The method further includes, by the controller, responsive to the same blower motor request, operating the blower motor at a second speed less than the first speed responsive to the HCIV directing the coolant to an electric heater and not to the engine.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 15/951,366filed Apr. 12, 2018, the disclosure of which is hereby incorporated inits entirety by reference herein.

TECHNICAL FIELD

This disclosure relates to operation of blower motors, and moreparticularly, to operation of blower motors in hybrid electric vehiclesas a function of ambient temperature and vehicle operation mode.

BACKGROUND

A hybrid electric vehicle (HEV) can be propelled by an engine and anelectric machine energized by a traction battery. A plug-in hybridelectric vehicle (PHEV) includes a traction battery that can be chargedvia electrically connection to an external power source. A batteryelectric vehicle (BEV) does not include an engine and is propelled onlyby an electric machine. HEVs, PHEVs and BEVs are three examples ofvehicles that are at least partially propelled by an electric machine.In such applications, a traction battery can include a battery packhaving individual cells that are charged and discharged duringoperation. The traction battery may also discharge electric power fromand transfer electric power between the cells during cell balancingoperations.

In addition to propelling the vehicle, electric power may be used tosupply onboard auxiliary loads. For example, electric power may bedelivered to blower motors as used in a climate control system of thevehicle.

SUMMARY

In at least one approach, a method of operating a vehicle climate systemis provided. the method may include, by a controller, responsive to asame blower motor, operating a blower motor at a first speed responsiveto a heater core isolation valve (HCIV) directing coolant used to heat acabin to an engine. The method may also include operating the blowermotor at a second speed less than the first speed responsive to the HCIVdirecting the coolant to an electric heater and not to the engine.

In at least one approach, a method of operating a vehicle climate systemis provided. The method may include, by a controller, responsive to asame blower motor request, operating a blower motor at a first voltagewhen a heater core isolation valve (HCIV) is in a first configuration.The method may further include, by the controller, responsive to ablower motor request, operating the blower motor at a second voltagelower than the first voltage when the HCIV is in a second configuration.

In at least one approach, a method of operating a vehicle climate systemis provided. The method may include, by a controller, responsive to ablower motor request, operating a blower motor at a first voltage whenan engine coolant temperature (ECT) is higher than a heater coretemperature (HCT). The method may further include, by the controller,responsive to a blower motor request, operating the blower motor at asecond voltage lower than the first voltage when the ECT is lower thanthe HCT.

In at least one approach, a method of operating a vehicle climate systemis provided. The method may include, by a controller, responsive to asame blower motor setting and ambient temperature being less than apredefined threshold, reducing a same blower motor voltage and modifyinga user-interface to indicate a decreased maximum blower motor speedresponsive to a heater core isolation valve (HCIV) configuration changefrom a first configuration to a second configuration. The method mayfurther include, by the controller, responsive to the same blower motorsetting and ambient temperature being less than the predefinedthreshold, maintaining the same blower motor voltage and modifying theuser-interface to indicate an increased maximum blower motor speedresponsive to a HCIV configuration change from the second configurationto the first configuration.

In at least one approach, a method of operating a vehicle climate systemis provided. The method may include, by a controller, responsive to asame blower motor setting and ambient temperature being less than apredefined threshold, maintaining a same blower motor voltage andmodifying a user-interface to indicate increased blower motor speedcapacity responsive to a change from charge deplete mode to chargesustain mode. The method may further include by a controller, responsiveto the same blower motor setting and ambient temperature being less thana predefined threshold, reducing the blower motor voltage and modifyingthe user-interface to indicate decreased blower motor speed capacityresponsive to a change from the charge sustain mode to the chargedeplete mode.

In at least one approach, a method of operating a vehicle climate systemis provided. The method may include, by a controller, when an ambienttemperature is less than a threshold, responsive to a mode change from acharge deplete mode to a charge sustain mode, maintaining a blower motorvoltage and modifying a user-interface indicator. The method may furtherinclude, by the controller, when the ambient temperature is less thanthe threshold, responsive to a mode change from the charge sustain modeto the charge deplete mode, reducing the blower motor voltage andmodifying the user-interface indicator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a vehicle having an electric machineand engine.

FIG. 2 is a schematic representation of vehicle components implementinga climate control strategy.

FIG. 3 is a flow chart of a blower motor control algorithm.

FIG. 4 is another flow chart of a blower motor control algorithm.

FIG. 5 is still another flow chart of a blower motor control algorithm.

FIG. 6 is still another flow chart of a blower motor control algorithm.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to beunderstood, however, that the disclosed embodiments are merely examplesand other embodiments may take various and alternative forms. Thefigures are not necessarily to scale; some features could be exaggeratedor minimized to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a representative basis forteaching one skilled in the art to variously employ the presentinvention. As those of ordinary skill in the art will understand,various features illustrated and described with reference to any one ofthe figures may be combined with features illustrated in one or moreother figures to produce embodiments that are not explicitly illustratedor described. The combinations of features illustrated providerepresentative embodiments for typical applications. Variouscombinations and modifications of the features consistent with theteachings of this disclosure, however, could be desired for particularapplications or implementations.

Hybrid vehicles, such as hybrid electric vehicles (HEVs) and plug-inhybrid electric vehicles (PHEVs), are provided with more than one sourceof power. Besides the gasoline fuel energy, a hybrid vehicle also has anadditional energy source of electrical energy stored in the battery,which may be electric energy from the electric grid deposited in thevehicle's battery during charging. The power management of the hybridvehicle allocates the drive power demand of the vehicle to one or bothof the two energy sources in order to achieve an improved fuel economyand meet the other comparable HEV/PHEV control objectives. Whileconventional HEVs may be operated in order to maintain the battery Stateof Charge (SOC) around a constant level, it may be desirable for PHEVsto use as much pre-saved battery electric (grid) energy as possiblebefore the next charge event (when the vehicle is “plugged-in”). Toincrease fuel economy, electric energy may be preferentially used tosave as much gasoline fuel as possible.

FIG. 1 depicts an electrified vehicle 112 that may be referred to as aplug-in hybrid-electric vehicle (PHEV). The vehicle 112 may comprise oneor more electric machines 114 mechanically coupled to a hybridtransmission 116. The electric machines 114 may be capable of operatingas a motor or a generator. In addition, the hybrid transmission 116 ismechanically coupled to an engine 118. The power plant of the vehiclemay include any number of energy production or maintenance machines(e.g., engines, batteries, capacitors, solar panels, fuel cells,electric machines). The hybrid transmission 116 is also mechanicallycoupled to a drive shaft 120 that is mechanically coupled to the wheels122. The electric machines 114 can provide propulsion and decelerationcapability when the engine 118 is turned on or off. The electricmachines 114 may also act as generators and can provide fuel economybenefits by recovering energy that would normally be lost as heat in afriction braking system. The electric machines 114 may also reducevehicle emissions by allowing the engine 118 to operate at moreefficient speeds and allowing the hybrid-electric vehicle 112 to beoperated in electric mode with the engine 118 off under certainconditions. An electrified vehicle 112 may also be a battery electricvehicle (BEV). In a BEV configuration, the engine 118 may not bepresent. In other configurations, the electrified vehicle 112 may be afull hybrid-electric vehicle (FHEV) without plug-in capability.

The vehicle 112 may be operated in a plurality of different powertrainmodes including charge-sustaining mode and charge-depleting mode (alsoknown as EV mode). In charge-depleting mode, the battery is used as theprimary source for propulsion until the battery SOC drops below athreshold SOC, at which point, the vehicle switches to charge-sustainingmode. Used herein, the term charge-depletion mode refers to modes wherethe engine may run periodically and to modes where the engine is notused. For example, the vehicle may include an EV-only mode (also knownas EV now) where the engine is disabled.

A traction battery or battery pack 124 stores energy that can be used bythe electric machines 114. The vehicle traction battery pack 124 mayprovide a high voltage direct current (DC) output. The traction battery124 may be electrically coupled to one or more power electronic modules126. One or more contactors 142 may isolate the traction battery 124from other components when opened and connect the traction battery 124to other components when closed. The power electronic module 126 is alsoelectrically coupled to the electric machines 114 and provides theability to bi-directionally transfer energy between the traction battery124 and the electric machines 114. For example, a traction battery 124may provide a DC voltage while the electric machine 114 may operate witha three-phase alternating current (AC) to function. The power electronicmodule 126 may convert the DC voltage to a three-phase AC current tooperate the electric machine 114. In a regenerative mode, the powerelectronic module 126 may convert the three-phase AC current from theelectric machine 114 acting as generators to the DC voltage compatiblewith the traction battery 124.

The vehicle 112 may include a variable-voltage converter (VVC) 144electrically coupled between the traction battery 124 and the powerelectronic module 126. The VVC 144 may be a DC/DC boost converterconfigured to increase or boost the voltage provided by the tractionbattery 124. By increasing the voltage, current requirements may bedecreased leading to a reduction in wiring size for the power electronicmodule 126 and the electric machine 114. Further, the electric machine114 may be operated with better efficiency and lower losses.

In addition to providing energy for propulsion, the traction battery 124may provide energy for other vehicle electrical systems. The vehicle 112may include a DC/DC converter module 128 that converts the high voltageDC output of the traction battery 124 to a low voltage DC supply that iscompatible with low-voltage vehicle loads. An output of the DC/DCconverter module 128 may be electrically coupled to an auxiliary battery130 (e.g., 12V battery) for charging the auxiliary battery 130. Thelow-voltage systems may be electrically coupled to the auxiliary battery130.

One or more electrical loads may be coupled to the high-voltage bus. Theelectrical loads may have an associated controller that operates andcontrols the electrical loads when appropriate. An example electricalload may be a heater 146, such as a positive temperature coefficient(PTC) heater, a resistive heater, or other type of heater. Otherexamples of high voltage electrical loads include an air-conditioningcompressor.

The vehicle 112 may be an electric vehicle or a plug-in hybrid vehiclein which the traction battery 124 may be recharged by an external powersource 136. The external power source 136 may be a connection to anelectrical outlet. The external power source 136 may be electricallyconnected to electric vehicle supply equipment (EVSE) 138. The EVSE 138may provide circuitry and controls to regulate and manage the transferof energy between the power source 136 and the vehicle 112. The externalpower source 136 may provide DC or AC electric power to the EVSE 138.The EVSE 138 may have a charge connector 140 for plugging into a chargeport 134 of the vehicle 112. The charge port 134 may be any type of portconfigured to transfer power from the EVSE 138 to the vehicle 112. Thecharge port 134 may be electrically connected to a charger or onboardpower conversion module 132. The power conversion module 132 maycondition the power supplied from the EVSE 138 to provide the propervoltage and current levels to the traction battery 124. The powerconversion module 132 may interface with the EVSE 138 to coordinate thedelivery of power to the vehicle 112. The EVSE connector 140 may havepins that mate with corresponding recesses of the charge port 134.Alternatively, various components described as being electricallyconnected may transfer power using a wireless inductive coupling.

Electronic modules in the vehicle 112 may communicate via one or morevehicle networks. The vehicle network may include a plurality ofchannels for communication. One channel of the vehicle network may be aserial bus such as a Controller Area Network (CAN). One of the channelsof the vehicle network may include an Ethernet network defined byInstitute of Electrical and Electronics Engineers (IEEE) 802 family ofstandards. Additional channels of the vehicle network may includediscrete connections between modules and may include power signals fromthe auxiliary battery 130. Different signals may be transferred overdifferent channels of the vehicle network. For example, video signalsmay be transferred over a high-speed channel (e.g., Ethernet) whilecontrol signals may be transferred over CAN or discrete signals. Thevehicle network may include any hardware and software components thataid in transferring signals and data between modules. The vehiclenetwork is not shown in FIG. 1 but it may be implied that the vehiclenetwork may connect to any electronic module that is present in thevehicle 112.

A vehicle system controller (VSC) 148 may be present to coordinate theoperation of the various components. The VSC 148 may also be adapted tocontrol a powertrain operating mode of the vehicle 112. For example, theVSC 148 can provide an input to the powertrain that causes thepowertrain to operate in at least a charge-sustaining (CS) mode or acharge-depleting (CD) mode. In the CS mode, the engine 118, the electricmachine 114, or both can power the drive wheels 122. The CS mode isgenerally considered a default powertrain mode for normal operation ofthe electrified vehicle. In at least one approach, the engine may run,but not necessarily continuously, in CS mode.

In the CD mode, the drive wheels 122 are powered by the electric machine114, but not the engine 118. The CD mode is generally considered anelectric-only operating mode.

In at least one approach, the CD mode may be an available drive modewhen the ambient temperature is above a threshold temperature (e.g., 10degrees Celsius (° C.)). As used herein, ambient temperature may referto the outside ambient temperature; i.e., the temperature outside of thevehicle. In conditions in which the ambient temperature is below athreshold temperature, a drive mode that utilizes the engine 118 topower the drive wheels 122 (such as the CS mode) may be required. In atleast another approach, the CD mode may also be an available drive modewhen a fluid temperature (e.g., a transmission fluid temperature) isabove a threshold fluid temperature.

The vehicle 112 includes a climate control system 150 that includes theheater 146, one or more sensors 152 a, 152 b, a variable blower control(VBC) 154 in communication with a blower motor 156 that is adapted tooperate a blower fan, and a climate controller 158 in communication withthe heater 146, the sensors 152 a, 152 b, and the VBC 154.

The sensors 152 a, 152 b may be temperature sensors. In at least oneapproach, a first temperature sensor 152 a may be configured todetermine, directly or indirectly, an ambient air temperature at anexterior of the vehicle 112. A second temperature sensor 152 b may beconfigured to determine, directly or indirectly, a cabin air temperatureat an interior of the vehicle 112.

The blower motor 156 may be may be a variable speed blower motor fordelivering air to an interior cabin of the vehicle 112. In this way, inresponse to a signal from the VBC 154, the blower motor 156 may vary afan speed of the blower fan.

The climate controller 158 may be a microprocessor-based controllerhaving a central processing unit, internal memory such as RAM and/orROM), and associated inputs and outputs communicating across a bus. Theclimate controller 158 may be a portion of a central vehicle maincontrol unit or a stand-alone unit. The climate controller 158 mayinclude various processing units which may be incorporated as separatedevices or as an integral part of the climate controller 158. Theclimate controller 158 may, as is described in greater detail below,control the various motors and actuators of the climate control systembased upon the various sensor and control inputs and in accordance withprogrammed logic or algorithms.

The VBC 154, having any suitable processor, may be in electricalcommunication with the blower motor 156 via electrical ports, which maycorrespond to the positive and negative input of the blower motor 156.The VBC 154 may include other connections such as a ground connection ora pulse width modulation (PWM) input from the climate controller 158. Ingeneral, the VBC 154 receives a blower speed value at the PWM input fromthe climate controller 158, and subsequently the VBC 154 changes therevolution speed of the blower motor 102. Alternatively, the VBC 154 mayreceive a DC voltage, and this DC voltage may be converted to acorresponding PWM signal. In addition, alternate control modules such asan Electronic Automatic Temperature Control (EATC), a Remote ClimateControl Module (RCCM), a Dual Automatic Temperature Control (DATC), mayalso be employed to monitor the blower motor 156.

One possible system for providing passenger compartment heating for aPHEV is shown in FIG. 2 . The system provides two sources of coolantheating. The system may utilize heat from the engine 118 to heat thecoolant as in a conventional ICE vehicle. The system may also provideheat via an electric heater 146. Having multiple sources of heat allowsflexibility during normal operating conditions and some redundancyduring failure modes. The system allows the coolant from the differentheat sources to flow through a heater core. The addition of a HeaterCore Isolation Valve (HCIV) 170 allows the passenger heater system toselect the source of heated coolant. A vehicle system controller (VSC)(148 in FIG. 1 ) may control the operation of the system. The VSC maydetermine the heating mode based on the passenger-heating request andthe status of the various components in the heating system. To ensurerobust operation, the VSC may attempt to work with missing or failedcontrol elements by choosing an appropriate operating mode.

The system may also have an auxiliary water pump 174 to force coolant toflow through the system. A coolant sensor 186 may be included to measurethe coolant temperature entering the heater core 176. The coolant flowsthrough a heater core 176 to allow heat to be transferred from thecoolant to air entering the passenger compartment. The heat may betransferred from the coolant in the heater core 176 using a blowerassembly 188 (which may correspond to the blower motor 156 of FIG. 1 )to pass air over the heater core 176 and into the passenger compartment.

A coolant sensor 196 may also or may instead be included to measure thecoolant temperature exiting from an outlet (or output) the heater core176.

The system may also have a water pump 180 to force coolant to flowthrough the engine 118. The water pump 180 may be mechanically orelectrically driven. In certain modes, the water pump 180 may forcecoolant through the heater core 176 as well. The system may also have aradiator 184 to dissipate heat in the coolant. The system may also havea thermostat 182 to control the flow of coolant between the radiator 184and the engine 118. The system may also have a degas bottle 190 that mayact as a coolant reservoir, remove air from the coolant, and providepressure relief. The cooling system may further include an exhaust gasrecirculation (EGR) 192 system that recirculates a portion of theengine's exhaust gas back to the intake manifold. In addition, thesystem may have an engine coolant temperature sensor 194 to determinethe coolant temperature exiting the engine 118 or the engine coolanttemperature exiting the engine may be estimated or inferred from othermeasurements such as a cylinder head temperature sensor 198.

The system may also have a cylinder head temperature (CHT) sensor 198.The CHT 198 sensor may be adapted to record the cylinder headtemperature at the engine 118.

The HCIV 170 may be used to activate different coolant loops primarilyfor cabin heating. In one position, the HCIV 170 forms an electric-onlyheating loop 172 (also referred to herein as an “isolated loop”). Inthis position, the coolant flows in a loop comprised of the HCIV 170,the auxiliary water pump 174, the electric heater 146, and a heater core176, not limited to that particular order. In another position, the HCIV170 forms a combined heating loop 178 that passes through the engine118. In the combined heating loop 178, coolant flows through the HCIV170, thermostat 182, water pump 180, engine 118, auxiliary water pump174, electric heater 146, and heater core 176, not limited to thatparticular order. There is also a separate engine loop in which coolantflows through engine 118, radiator 184, water pump 180, and thethermostat 182, not necessarily in that order. Depending on the mode ofoperation, in order for coolant to flow in the system one or both of thepumps, 174 or 180, may be activated. As shown in FIG. 1 , another loopthat includes the engine 118, a bypass, the thermostat 182, and thewater pump 180 may be active when the thermostat 182 closes off flowthrough the radiator 184.

The system has the capability to alter the flow of coolant through thesystem in response to the desired source of coolant heating. Based onthe position of the HCIV 170, coolant may flow in different loops.Separate coolant temperatures may be achieved in each loop depending onthe heating/cooling requirements of each loop at a particular time. Theaddition of the HCIV 170 allows the coolant flow to be modified. TheHCIV 170 may be an electrically switched valve that alters the flow ofcoolant through the system. The HCIV 170 may be a three-port valve thatallows one inlet port to be alternately connected to each of the othertwo outlet ports based on an activation signal. The HCIV 170 may allowthe coolant loops to be combined as one larger coolant loop. The HCIV170 may be switched in such a way to allow coolant to flow from theengine coolant loop through the HCIV 170 to the electric-only heaterloop to operate the cabin heating in the electric-only heating loop 172,or with the combined heating loop 178 with the engine 118.

A controller may be used to actuate the HCIV 170. In at least oneapproach, a solenoid and spring assembly may be used to set a positionof the HCIV 170. Depending on the design of the HCIV 170, it may or maynot have feedback as to the actual position of the HCIV 170. Theposition of the HCIV 170 may be ascertained by observing the behavior ofthe system during operation. In at least one approach, the position ofthe HCIV 170 may be inferred from a temperature of coolant exiting theheater core; for example, as determined by sensor 196, or as otherwiseinferred. In at least another approach, the position of the HCIV 170 maybe inferred from a temperature of coolant entering the heat exchangerand a temperature of coolant exiting the engine (for example, asdetected at the heater coolant temperature sensor 186 and at the enginecoolant temperature sensor).

Referring again to FIG. 1 , the climate controller 158 may be adapted tosend signals to the VBC 154 to control the speed of the blower motor 156according to various blower parameters. In at least one approach, theVBC 154 may control the speed of the blower motor 156 according to acurrent input at the blower motor 156. In at least one other approach,the VBC 154 may control the speed of the blower motor 156 according tovoltage input at the blower motor 156. In at least one other approach,the VBC 154 may control the speed of the blower motor 156 according to aspeed (e.g., revolutions per minutes) at the blower motor 156. Theparameters contemplated herein may be discrete values at which theblower motors are operated, or may merely be upper limits of values atwhich the blower motors may be operated. For example, a blower motorthat is operated at 13 V may be operated at any voltage up to andincluding 13 V.

Control of the blower motor 156 allows a vehicle occupant to select adesired air flow rate by setting a fan speed to, for example, OFF, LOW,MED, HIGH, or AUTO. At the LOW, MED, and HIGH settings, a specificvoltage may be supplied to blower motor 156. The voltage applied maycorrespond to the respective desired air flow rates. At the AUTOsetting, the voltage supplied to blower motor 156 is controlled by theclimate controller 158 (to be described in more detail below) asnecessary to achieve desired conditions.

The climate controller 158 may be adapted to provide a manualtemperature control mode. When an air flow rate (blower speed) isselected by an occupant, the climate controller 158 sends a signal toset the voltage powering the blower motor 156. The voltage to be usedmay depend on the operating mode selected and may be contained inlook-up tables in the memory of climate controller 158.

The climate controller 158 may also be adapted to provide an automaticclimate control mode for automatically controlling the climate withinthe cabin of the vehicle. An automatic climate control mode may allowthe climate controller 158 to regulate passenger cabin temperature aswell as control various climate control functions automatically basedupon environmental conditions and/or vehicle operating characteristics.For example, when the AUTO setting is selected, the climate controller158 may apply preprogrammed logic and memory to determine and direct,based upon sensor and operator control inputs, the correct temperature,mode, and blower speed required to achieve maximum comfort in the cabin.When such an automatic mode is selected, the climate controller 158 mayvary the blower speed by adjusting the voltage powering the blower motor156 anywhere between zero volts (blower off) and the maximum systemvoltage (blower full speed). A passenger vehicle may, for example,utilize a 9 volt (9V) or a 14 volt (14V) electrical system. For theexample discussed in this disclosure, 14V shall be considered to equateto blower full speed. Some blower motors cannot operate properly atvoltages below a certain lower limit. In the example system describedherein, the designed minimum operating voltage for the blower motor maybe assumed to be 4 volts.

In this way, a driver may input (e.g., at a center console of thevehicle 112) a control such as a target or set point cabin temperature,and data supplied by sensors (e.g., second sensor 152 b) may be used tointroduce appropriately temperature-controlled and/or air-conditionedair into the passenger cabin to adjust the cabin temperature as desiredby the user. For example, if the measured temperature of the interiorair is below the desired temperature, then the air stream supplied tothe cabin may be heated more strongly or cooled to a lesser degree,and/or the intensity (rate of flow) of the heated or cooled air streamis correspondingly changed.

When the vehicle 112 is operated in a charge sustaining mode, the engine118 is on and may be used as a heat source for heating air that issupplied to the cabin of the vehicle 112. For example, the vehicle 112may utilize engine waste heat absorbed by an engine cooling system toprovide cabin heating to a plurality of heat exchangers.

However, in a CD mode, the engine 118 is shut off and may be unavailableto act as heat source. In this way, the vehicle 112 may be provided witha heater 146. The heater 146 may apply heat into a cooling circuit sothat the cabin of the vehicle 112 can be heated while keeping the engine118 off.

In many instances, the climate control system 150, as operated by theclimate controller 158, requires significantly more time to heat thepassenger cabin to the desired temperature when the heater 146 is theonly heat source (e.g., in the CD mode), as compared to when the engine118 is available as a heat source (e.g., in the CS mode).

As such, when the vehicle is operated in the CD mode in certain coldconditions (such as when the ambient temperature is in the range ofapproximately 0 to approximately 10° C.), the blower motor 156 may blowrelatively cold air into the cabin for a greater amount of time ascompared to if the vehicle 112 were operated in the CS mode. When theclimate control system 150 is also operating in an automatic temperaturecontrol mode, the user may be surprised by a sustained discharge of coolair.

In this way, in at least one approach, the climate control system 150may be provided with mode-dictated operating conditions. Moreparticularly, the climate controller 158 may be adapted to operate theblower motor 156 according to a first set of parameters when the vehicle112 is operated in a first drive mode when the ambient temperature is ator below a predefined temperature, and to operate the blower motor 156according to a second set of parameters when the vehicle 112 is operatedin a second drive mode when the ambient temperature is at or below thepredefined temperature, and optionally, when the climate control system150 is in an automatic climate control mode.

The sets of parameters may be stored in a memory (e.g., in a memory ofclimate controller 158). The sets of parameters may be in the form of alook-up table, which includes at least one threshold temperature(T_(tN)) and at least one voltage parameter corresponding to thethreshold temperature. The threshold temperature may be a plurality ofthreshold temperatures (e.g., T₁, T₂, etc.), and may be referred to asstep temperatures. The voltage parameters may similarly be a pluralityof voltage parameters (e.g., V₁, V₂, etc.). The voltage parameters mayalso be a function of the climate control mode (e.g., automatic climatecontrol or manual climate control). An exemplary set of parameters isshown in Table 1 below.

TABLE 1 T (° C.) T_(t1) T_(t2) T_(t3) T_(t4) T_(t5) T_(t6) V_(AUTO) V₁V₂ V₃ V₄ V₅ V₆ V_(MANUAL) V₇ V₈ V₉ V₁₀ V₁₁ V₁₂

When an outside ambient temperature (T_(a)) is at or below a stepthreshold temperature (T_(t)), the climate controller 158 may be adaptedto operate the blower motor 156 according to an associated voltage. Theassociated voltage may be an upper limit such that the climatecontroller 158 may be adapted to operate the blower motor 156 at orbelow the associated voltage. In at least one approach,T_(t1)<T_(t2)<T_(t3)<T_(t4)<T_(t5)<T_(t6). As discussed in greaterdetail elsewhere herein, when the vehicle is operating in a first mode(e.g., a CS mode) and the climate control system is operating in anautomatic climate control mode, the voltages may be: V₁>V₂>V₃=V₄=V₅<V₆.When the vehicle is operating in the first mode (e.g., CS mode) and theclimate control system is operating in a manual climate control mode,the voltages may be: V₇=V₈=V₉=V₁₀=V₁₁=V₁₂. When the vehicle is operatingin a second mode (e.g., a CD mode) and the climate control system isoperating in an automatic climate control mode, the voltages may be:V₁<V₂<V₃<V₄<V₅<V₆. When the vehicle is operating in the second mode(e.g., CD mode) and the climate control system is operating in a manualclimate control mode, the voltages may be: V₇<V₈<V₉<V₁₀=V₁₁=V₁₂.

The voltages provided in the tables set forth herein may be maximumvoltages for a step threshold temperature. As such, the climatecontroller 158 may be adapted to operate the blower motor 156 accordingto voltages less than the maximum voltage for a step thresholdtemperature.

As discussed, the climate controller 158 may be adapted to operate theblower motor 156 according to a first set of parameters when the vehicle112 is operated in a first drive mode (such as a CS mode) when theambient temperature is at or below a predefined temperature, and tooperate the blower motor 156 according to a second set of parameterswhen the vehicle 112 is operated in a second drive mode (such as a CDmode) when the ambient temperature is at or below the predefinedtemperature. In many approaches, at may be desirable to correlate blowerspeeds (e.g., as a function of voltages) for noise, vibration, andharshness (NVH) reasons.

In at least one approach, when the engine 118 is being used to propelthe vehicle (CS mode), the climate controller 158 may be adapted tooperate the blower motor 156 according to the first set of parameters.An exemplary first set of parameters is shown in Table 2 below.

TABLE 2 T (° C.) −10 −5 0 5 16 32 V_(AUTO) 11 10.5 9 9 9 11 V_(MANUAL)13.5 13.5 13.5 13.5 13.5 13.5

As shown in Table 2, the climate controller 158 may be adapted tooperate the blower motor 156 according to the same (or similar) voltageparameters when the ambient temperature corresponds to the variousthreshold temperatures. This may be, for example, because operation ofthe engine 118 in the first drive mode may heat (or have the capabilityto heat) the air to be passed into the passenger cabin to a desiredtemperature in a relatively short period of time (e.g., 6 minutes). Assuch, a reduction in voltage to the blower motor 156 may be unnecessary.

When the electric machine 114 and not the engine 118 is propelling thevehicle, the engine 118 may not be available to heat the air to bepassed into the passenger cabin. Instead, the heater 146 may be the sole(or primary) source of heat. The heater 146 may heat the air to bepassed into the passenger cabin to a desired temperature at a relativelyslower rate than the engine 118, or the heater 146 may not be capable ofheating the air to be passed into the cabin to an adequate temperature.In this way, when the electric machine 114 and not the engine 118 ispropelling the vehicle, the climate controller 158 may be adapted tooperate the blower motor 156 according to the second set of parameters.An exemplary second set of parameters is shown in Table 3 below.

TABLE 3 T (° C.) −10 −5 0 5 16 32 V_(AUTO) 7 8 8.5 9 9 11 V_(MANUAL) 910 11.5 13.5 13.5 13.5

As shown, the climate controller 158 may reduce the voltage foroperating the blower motor 156 as a function of the ambient temperaturewhen the electric machine 114 and not the engine 118 is propelling thevehicle. In this way, the maximum speed of the blower fan may bereduced, so as to reduce airflow into the passenger cabin.

In an optional approach, the climate controller 158 may reduce thevoltage for operating the blower motor 156 as an additional function ofthe climate control mode. For example, when the vehicle is operating inan automatic climate control mode, the climate controller 158 may reducethe voltage for operating the blower motor 156 according to a first modestrategy, such as V_(AUTO) strategy shown in Table 3. When the vehicleis operating in a manual climate control mode, the climate controller158 may reduce the voltage for operating the blower motor 156 accordingto a second mode strategy, such as V_(MANUAL) strategy shown in Table 3.As shown, the voltages in the second mode strategy may be greater thanthe voltages in the first mode strategy for a given thresholdtemperature.

Referring to FIG. 3 , a method 200 of operating a vehicle climate systemwhen an ambient temperature is below a threshold temperature is shown.The method 200 begins with start 202, which may correspond, for example,to a vehicle startup routine, such as when a user turns on or activatesone or more vehicle systems (e.g., when a key fob is within a proximityof the vehicle, when a user presses a vehicle startup button, or when auser inserts a key into a receptacle of the vehicle). The method 200 mayalso or instead start 202 after a vehicle startup routine, such asduring a drive event. In this way, the method 200 may be initiated, forexample, in response to a battery state of charge (SOC) reaching orfalling to a threshold SOC.

At step 204, a vehicle operation mode is determined. For example, atstep 204, it may be determined whether an engine is being used to propelthe vehicle. In at least one approach, the method may include the stepof receiving (e.g., at a controller such as climate controller 158) asignal indicative of a vehicle operation mode. The signal may betransmitted, for example, by a controller adapted to control the vehicleoperation mode (e.g., VSC 148). In at least one approach, the vehicleoperating state is a CAN signal sent from VSC 148 to the climatecontroller 158. The vehicle operation mode may be at least one of afirst vehicle operation mode, such as a CS mode wherein the engine isbeing used to propel the vehicle, and a second vehicle operation mode,such as a CD mode wherein the traction battery and not the engine isbeing used to propel the vehicle.

When an engine is being used to propel the vehicle (e.g., when thevehicle is operating in a CS mode), the method 200 may proceed to 206wherein the blower motor is operated according to a first blowerparameter. The first blower parameter may correspond to a parameterprovided in Table 2 above, and may be, for example, a first voltage foroperating the blower motor.

When an engine is not being used to propel the vehicle, such as when anelectric machine is the primary or only source of vehicle propulsion(e.g., when the vehicle is operating in a CD mode), the method 200 mayproceed to step 208. At step 208, it is determined (e.g., at acontroller such as climate controller 158) whether an ambienttemperature (e.g., outside ambient temperature) is below a thresholdtemperature. The threshold temperature may be, for example, in the rangeof approximately 0 to approximately −10° C.

If the ambient temperature is not below the threshold temperature, themethod 200 may proceed to 206 wherein the blower motor is operatedaccording to a first blower parameter.

If the ambient temperature is below the threshold temperature, themethod 200 may proceed to 210, wherein the blower motor is operatedaccording to a second blower parameter. The second blower parameter maycorrespond to a parameter provided in Table 3 above, and may be a secondvoltage for operating the blower motor. The second blower parameter maybe different than the first blower parameter. For example, the secondvoltage may be lower than the first voltage.

In at least one optional approach, when operating according to the firstblower parameter, the method 200 may include the additional step 212 ofdetermining if an automatic climate control mode is enabled. Theautomatic climate control mode may, for example, include a target cabintemperature, which may be a user-defined target cabin temperature. Inresponse to determining the automatic climate control mode is enabled,the method may include operating 214 the blower motor according to afirst subparameter of the first blower parameter. The first subparametermay correspond, for example, to the V_(AUTO) parameters in Table 2above. In response to determining the automatic climate control mode isnot enabled, the method may include operating 216 the blower motoraccording to a second subparameter of the first blower parameter. Thesecond subparameter may correspond, for example, to the V_(MANUAL)parameters in Table 2 above.

In at least one optional approach, when operating according to thesecond blower parameter, the method 200 may include the additional step218 of determining if an automatic climate control mode is enabled. Inresponse to determining the automatic climate control mode is enabled,the method may include operating 220 the blower motor according to athird subparameter of the second blower parameter. The thirdsubparameter may correspond, for example, to the V_(AUTO) parameters inTable 3 above. In response to determining the automatic climate controlmode is not enabled, the method may include operating 222 the blowermotor according to a fourth subparameter of the second blower parameter.The fourth subparameter may correspond, for example, to the V_(MANUAL)parameters in Table 3 above.

In at least one approach, multiple threshold temperatures may beprovided. For example, the threshold temperature may include at least afirst step temperature and a second step temperature. The second steptemperature may be lower than the first step temperature.

In at least one approach, the second blower parameter may include atleast a first voltage that may, for example correspond to the first steptemperature, and a second voltage that may, for example, correspond tothe second step temperature. The second voltage may be lower than thefirst voltage. In this way, when the traction battery and not the engineis being used to propel the vehicle, the climate controller may beadapted to operate the blower motor at the first voltage when theambient temperature corresponds to the first step temperature, and tooperate the blower motor at the second voltage when the ambienttemperature corresponds to the second step temperature.

In at least one approach, the first blower parameter may include atleast a third voltage that may, for example correspond to the first steptemperature, and a fourth voltage that may, for example correspond tothe second step temperature. The third voltage may be greater than thefirst voltage. The fourth voltage may be lower than the third voltage,and may be greater than the second voltage. In this way, when the engineis being used to propel the vehicle, the climate controller may beadapted to operate the blower motor at the third voltage when theambient temperature corresponds to the first step temperature, and tooperate the blower motor at the fourth voltage when the ambienttemperature corresponds to the second step temperature.

In at least one approach, the method may further include changingvehicle operation modes when the ambient temperature is below athreshold ambient temperature. For example, the vehicle operation modemay change from a pure-electric to an engine-propelled mode or hybridmode when the ambient temperature is below −10° C.

In at least one approach, when a vehicle operation mode is changed froma pure electric mode (e.g., CD mode) to engine or hybrid mode (e.g., CSmode), the method may include determining a HCIV position beforeswitching between sets of blower parameters. The method may also, orinstead, include determining a delta between an engine coolanttemperature and heater core temperature before switching between sets ofblower parameters. This may be, for example, because the engine coolanttemperature may take several minutes to warm up to the heater corecoolant temperature before the HCIV moves to an open position. If thecontrol head switches to the first blower parameter table immediatelyafter the vehicle operation mode is switched from a CD mode to a CSmode, and where the engine coolant temperature may be still much colderthan heater core coolant temperature, the discharge air temperature maydrop significantly and may cause user discomfort due to the blowing ofcold air.

In at least one approach, a method of operating a vehicle climate systemwhen an ambient temperature is below a threshold temperature isprovided. The method may include, responsive to ambient temperaturesless than a threshold, operating a blower motor at a voltage thatdepends on whether the vehicle is in charge sustain mode or chargedeplete mode. In the charge sustain mode, an engine may be used topropel the vehicle. In the charge deplete mode, an electric machine andnot the engine may be used to propel the vehicle. The method may furtherinclude responsive to ambient temperatures greater than the threshold,operating the blower motor at a voltage that does not depend on whetherin the charge sustain or charge deplete modes.

The method may further include, responsive to ambient temperatures lessthan the threshold, operating the blower motor at a first voltage whenthe vehicle is in the charge sustain mode, and operating the blowermotor at a second voltage less than the first voltage when the vehicleis in the charge deplete mode.

The method may further include, responsive to a battery state of charge(SOC) being less than a SOC threshold when the vehicle is in the chargedeplete mode, using an engine to propel the vehicle. The method mayfurther include operating the blower motor at the first voltage.

In at least one approach, a method of operating a vehicle climate systemwhen an ambient temperature is below a threshold temperature isprovided. The method may include, responsive to ambient temperaturesless than a threshold, operating a blower motor at a voltage thatdepends on whether the vehicle climate system is operating in anautomatic climate control mode or a manual climate control mode. Themethod may further include, responsive to ambient temperatures greaterthan the threshold, operating the blower motor at a voltage that doesnot depend on whether the vehicle climate system is operating in theautomatic climate control mode or the manual climate control mode.

In at least one approach, the method may further include, responsive toambient temperatures less than the threshold, operating the blower motorat a voltage that further depends on whether the vehicle climate systemis operating in an automatic climate control mode or a manual climatecontrol mode.

In at least one approach, the method may further include, by thecontroller and responsive to ambient temperatures less than thethreshold, operating the blower motor at a first voltage when thevehicle climate system is operating in the automatic climate controlmode, and operating the blower motor at a second voltage greater thanthe first voltage when the vehicle climate system is operating in themanual climate control mode.

As discussed, the HCIV 170 may be adapted to operate in multipleconfigurations. In a first configuration, the HCIV 170 may be adapted todirect (e.g., by diverting, rerouting, blocking, or communicating)coolant from the heater core 176 through a combined heating loop 178that includes an engine coolant path. In a second configuration, theHCIV 170 may be adapted to direct coolant from the heater core 176through an electric-only heating loop 172 that does not include theengine coolant path.

Referring now to FIG. 4 , in at least one approach, a method 250 ofoperating a vehicle climate system is provided. The method 200 beginswith start 252. The method may include receiving 254 a blower motorrequest. The blower motor request may be, for example, a user inputreceived at a blower input, or may be an automatic blower request from acontroller. An automatic blower request may be automaticallycommunicated, for example, when a user turns on or activates one or morevehicle systems (e.g., when a key fob is within a proximity of thevehicle, when a user presses a vehicle startup button, or when a userinserts a key into a receptacle of the vehicle). In this way, a blowermotor request may be a setting set by at least one of the user and theclimate control system.

The method may further include determining 256 if a heater coreisolation valve (HCIV) is in a first configuration. In at least oneapproach, this determination may be made as a function of a signalreceived at a controller indicating whether the HCIV is in the firstconfiguration or in the second configuration. The signal may be, forexample, a control area network (CAN) signal or other suitable signalthat may be received from a controller (e.g., the system controller 148of FIG. 1 .) The signal may be a binary signal directly indicatingwhether the HCIV is in the first or second configuration. In stillanother approach, the controller may receive a signal indicating anengine coolant temperature (ECT) and a signal indicating a heater coretemperature (HCT). The signal indicative of the ECT may include atemperature reading from an engine coolant temperature sensor (e.g., ECTsensor 194 of FIG. 1 ). The signal indicative of the ECT may include mayalso or may instead include a cylinder head temperature (CHT) receivedfrom a cylinder head temperature sensor (e.g., cylinder head temperaturesensor 198 of FIG. 1 ). In this way, the CHT may be used to infer theECT.

The controller, responsive to the blower motor request, may be adaptedto operate 258 a blower motor at a first blower speed (e.g., at firstvoltage) when the HCIV is in a first configuration. If the HCIV is notin the first configuration, it may be determined that the HCIV is in thesecond configuration (as indicated at step 260). The controller,responsive to the blower motor request, may be adapted operate 262 theblower motor at a second blower speed (e.g., a second voltage) lowerthan the first blower speed (e.g., the first voltage) when the HCIV isin the second configuration.

As discussed, the controller may receive a signal indicating an enginecoolant temperature (ECT) and a signal indicating a heater coretemperature (HCT). In this way, the controller may be adapted to operatethe blower motor according to the various voltages as a function of acomparison of the ECT and the HCT. For example, in one approach, thecontroller may be adapted to operate the blower motor according to thefirst voltage when ECT>HCT, and may be adapted to operate the blowermotor according to the second voltage when ECT<HCT. In still anotherapproach, using an offset temperature value. More particularly, thecontroller may be adapted to operate the blower motor according to thefirst voltage when ECT>HCT−X, and may be adapted to operate the blowermotor according to the second voltage when ECT<HCT−X.

As such, in at least one approach, a method of operating a vehicleclimate system is provided. The method may include, by a controller,responsive to a blower motor request, operating a blower motor at afirst voltage when an engine coolant temperature (ECT) is higher than aheater core temperature (HCT). The method may further include, by thecontroller, responsive to a blower motor request, operating the blowermotor at a second voltage lower than the first voltage when the ECT islower than the HCT, or lower than a function of the HCT (e.g., heatercore outlet temperature).

The controller may further be adapted to operate a blower motor as afunction of vehicle mode. For example, when a vehicle is operating in acharge-sustaining (CS) mode, the coolant system may utilize heat fromthe engine to provide sufficiently heated air into the passengercompartment. As such, the controller may be adapted to operate theblower motor according to a full range of blower voltages. When avehicle is operating in a charge-depleting (CD) mode, the coolant systemmay not utilize heat from the engine to provide heated air into thepassenger compartment. As such, the controller may be adapted to operatethe blower motor according to a reduced range of blower voltages.

In certain conditions, such as when the vehicle is operating in a CDmode, the controller may further be adapted to operate the blower motoraccording to a plurality of voltages as a function of an outside ambientair temperature. More particularly, at various temperature thresholds,the controller may be adapted to operate the blower motor according tocorresponding voltage ranges. In one approach, maximum voltages of thevoltage ranges may be reduced as a function of reduced ambient airtemperatures.

An exemplary set of parameters is shown in the tables below. Theparameters set forth in Table 4 may be used when the HCIV valve is in afirst configuration (e.g., position or orientation). As discussed, inthe first configuration, the HCIV is adapted to direct coolant from theheater core through a combined heating loop that includes an enginecoolant path. The parameters set forth in Table 5 may be used when theHCIV valve is in a second configuration. In the second configuration,the HCIV is adapted to direct coolant from the heater core through anelectric-only heating loop that does not include the engine coolantpath. Although the parameters set forth in the tables reflect maximumblower motor voltages (e.g., maximum available blower motor voltages),other blower speed parameters are expressly contemplated.

TABLE 4 Ambient Air Temperature (° C.) −10 −5 0 5 16 32 Manual 1 4.0 4.04.0 4.0 4.0 4.0 Blower 2 4.9 4.8 4.7 4.6 4.7 5.0 Speed 3 5.9 5.6 5.4 5.35.5 6.0 Selector 4 6.8 6.4 6.1 5.9 6.2 7.0 Position 5 8.7 7.9 7.4 7.27.7 9.0 6 10.6 9.5 8.8 8.4 9.2 11.0 7 13.0 11.5 10.5 10.0 11.0 13.5

TABLE 5 Ambient Air Temperature (° C.) −10 −5 0 5 16 32 Manual 1 4 4 4 44 4 Blower 2 4.3 4.4 4.5 4.5 4.7 5 Speed 3 4.6 4.8 4.9 5.1 5.5 6Selector 4 4.9 5.3 5.4 5.6 6.2 7 Position 5 5.6 6.1 6.4 6.6 7.7 9 6 6.26.9 7.3 7.7 9.2 11 7 7 8 8.5 9 11 13.5

In this way, when the HCIV is in the second configuration, thecontroller may be adapted to operate the blower motor according to afirst maximum voltage (e.g., 8.5V) when the ambient air temperature(e.g., 4° C.) is lower than a first temperature threshold (e.g., 5° C.)and a user-selectable blower speed is a first speed (e.g., fan speed 7).The controller may further be adapted to operate the blower motoraccording to a second maximum voltage (e.g., 7.3V) less than the firstvoltage (e.g., 8.5V) when the ambient air temperature (e.g., 4° C.) isless than the first temperature threshold (e.g., 5° C.) and theuser-selectable blower speed is a second speed (e.g., fan speed 6)different than the first speed (e.g., fan speed 7).

The controller may further be adapted to operate the blower motoraccording to a third voltage (e.g., 9V) greater than the first voltage(e.g., 8.5V) when the ambient air temperature (e.g., 6° C.) is greaterthan the first temperature threshold (e.g., 5° C.) and less than asecond temperature threshold (e.g., 16° C.), and a user-selectableblower speed is the first speed (e.g., fan speed 7). The controller mayfurther be adapted to operate the blower motor according to a fourthvoltage (e.g., 7.7V) less than the third voltage (e.g., 9V) when theambient air temperature (e.g., 6° C.) is greater than the firsttemperature threshold (e.g., 5° C.) and less than a second temperaturethreshold (e.g., 16° C.) that is greater than the first temperaturethreshold, and the user-selectable blower speed is the second speed(e.g., fan speed 6).

As shown, the maximum blower speeds for various blower speed settings(e.g., in both a manual or automatic climate control mode) may beadjusted in a proportional manner as ambient temperature varies across aplurality of temperature thresholds.

Although discrete values are provided for exemplary purposes, it isexpressly contemplated that operating parameters may be interpolated(for example, as a function of ambient temperature) for a givenoperating mode.

Referring now to FIG. 5 , in at least one approach, a method 270 ofoperating a vehicle climate system is provided. In at least oneapproach, the method may be performed when the vehicle climate system isin a manual control mode in which the user may select a blower speed.The method 270 begins with start 272. The method may include receiving274 a mode change request (e.g., from a CS mode to a CD mode orvice-versa). If it is determined at 276 that the request for anoperation mode switch is from a CD mode to a CS mode, a controller maybe adapted to maintain 278 a blower motor voltage. In this way, avoltage may not be increased and a user may not be subjected to higherblower levels than requested, even though engine heating may now beavailable within the coolant loop.

In at least one approach, the method may include determining 280 if anambient temperature Ta is less than a threshold temperature Tt. Thethreshold temperature Tt may be, for example, 32° C. If the thresholdtemperature Ta is less than the ambient temperature Tt, the method mayinclude modifying 282 a user-interface indicator. The user-interfaceindicator may be, for example, a displayed representation of blower fanspeed that may be displayed on a display device within the passengercompartment and visible by a user. In this way, a user may be informedthat, although the fan speed may not have increased, more increased fanspeeds are now available to the user (e.g., due to the benefit of theengine now able to heat the coolant). If the threshold temperature Tt isnot less than the ambient temperature Ta, the method may includemaintaining 284 a user-interface indicator.

If it is determined at 276 that the request for an operation mode switchis from a CS mode to a CD mode, the method may include determining 286if an ambient temperature T_(a) is less than a threshold temperature Tt.The threshold temperature Tt may be, for example, 32° C., or may be 5°C. If the threshold temperature Tt is less than the ambient temperatureTa, the method may include reducing 288 a blower motor voltage. In thisway, in response to the loss of engine heat within the coolant loop, acontroller may be adapted to limit (or “clip”) a range of availablevoltages. The method may further include modifying 290 a user-interfaceindicator; for example, to indicate to a user that a fan speed has beenreduced.

If the threshold temperature Tt is not less than the ambient temperatureTa, the method may include maintaining 292 a blower motor voltage. Themethod may further include maintaining 294 a user-interface indicator.

In this way, a method may include, by a controller, when an ambienttemperature is less than a threshold, maintaining a blower motor voltageand modifying a user-interface indicator responsive to a mode changefrom a charge deplete mode to a charge sustain mode. The method mayfurther include reducing the blower motor voltage and modifying theuser-interface indicator responsive to a mode change from the chargesustain mode to the charge deplete mode.

Referring to FIG. 6 , a method 300 of operating a vehicle climate systemis provided. The method may begin at 302 and may include receiving 304 ablower motor setting. The blower motor setting may be, for example, auser input requesting a blower motor operation or a given blower motorspeed selector position. In still another approach, the receiving 304 ablower motor setting includes receiving a command from a controller. Inthis way, the blower motor setting may be an automatic setting by aclimate control system.

The method may further include monitoring 306 for a heater coreisolation valve (HCIV) configuration change. As discussed, the HCIV maybe configured to operate in a first configuration in which the HCIV isadapted to direct coolant from the heater core through a combinedheating loop that includes an engine coolant path. The HCIV may also beconfigured to operate in a second configuration in which the HCIV isadapted to direct coolant from the heater core through an electric-onlyheating loop that does not include the engine coolant path.

If a HCIV configuration change occurs, the method may includedetermining 308 if an ambient temperature Ta is less than a thresholdtemperature Tt. The threshold temperature Tt may be, for example, 32°C., or may be 5° C. If the threshold temperature Tt is not less than theambient temperature Ta, the method may return to 304 where blowermonitor settings are monitored.

In response to a HCIV configuration change from the second configurationto the first configuration, as indicated at 310, the method may includemaintaining 312 the same maximum blower motor speed. The method mayfurther include modifying 314 a user-interface, for example, to indicateincreased blower motor speed maximum (e.g., capacity).

In response to a HCIV configuration change from the first configurationto the second configuration, as indicated at 316, the method may includereducing 318 the maximum blower motor speed. The method may furtherinclude modifying 320 a user-interface, for example, to indicatedecreased blower motor speed maximum (e.g., capacity).

In the method 300 of FIG. 6 , the controller may be adapted to utilizedone or more parameter tables as a function of the HCIV position. Forexample, when the HVIC is in the first configuration, the controller mayoperate a blower motor according to the parameters of Table 4. Forexample, when the HVIC is in the second configuration, the controllermay operate the blower motor according to the parameters of Table 5.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms encompassed by the claims.The words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the disclosure. Aspreviously described, the features of various embodiments may becombined to form further embodiments of the invention that may not beexplicitly described or illustrated. While various embodiments couldhave been described as providing advantages or being preferred overother embodiments or prior art implementations with respect to one ormore desired characteristics, those of ordinary skill in the artrecognize that one or more features or characteristics may becompromised to achieve desired overall system attributes, which dependon the specific application and implementation. These attributes mayinclude, but are not limited to cost, strength, durability, life cyclecost, marketability, appearance, packaging, size, serviceability,weight, manufacturability, ease of assembly, etc. As such, embodimentsdescribed as less desirable than other embodiments or prior artimplementations with respect to one or more characteristics are notoutside the scope of the disclosure and may be desirable for particularapplications.

What is claimed is:
 1. A method of operating a vehicle climate system,comprising: by a controller, responsive to a same blower motor request,operating a blower motor at a first voltage when an engine coolanttemperature (ECT) is higher than a heater core temperature (HCT); andoperating the blower motor at a second voltage lower than the firstvoltage when the ECT is lower than the HCT.
 2. The method of claim 1further comprising: at the controller, receiving a signal indicative ofa cylinder head temperature and a signal indicative of a heater coreoutlet temperature, and operating the blower motor at the first orsecond voltage as a function of a comparison of the signals indicativeof the cylinder head temperature and the heater core outlet temperature.3. A method of operating a vehicle climate system, comprising: by acontroller, responsive to a same blower motor setting and ambienttemperature being less than a predefined threshold, reducing a samemaximum blower motor speed and modifying a user-interface to indicate adecreased maximum blower motor speed responsive to a heater coreisolation valve (HCIV) configuration change from a first configurationto a second configuration; and maintaining the same blower motor speedand modifying the user-interface to indicate increased maximum blowermotor speed responsive to a HCIV configuration change from the secondconfiguration to the first configuration.
 4. The method of claim 3wherein in the first configuration, the HCIV is adapted to directcoolant from a heater core through a combined heating loop that includesan engine coolant path, and wherein in the second configuration, theHCIV is adapted to direct coolant from the heater core through anelectric-only heating loop that does not include the engine coolantpath.
 5. The method of claim 3 wherein the user-interface includes avisual blower fan speed indicator displayed at a display.
 6. The methodof claim 3 further wherein the predefined threshold is a firstpredefined threshold, the method further comprising: by the controllerresponsive to the same blower motor setting, operating a blower motoraccording to a first blower motor voltage range having a first minimumvoltage and a first maximum voltage responsive to the ambienttemperature being lower than the first predefined threshold, operatingthe blower motor according to a second blower motor voltage range havinga second maximum voltage that is less than the first maximum voltageresponsive to the ambient temperature being lower than a secondpredefined threshold that is lower than the first predefined threshold,and operating the blower motor according to a third blower motor voltagerange having a third maximum voltage that is less than the secondmaximum voltage responsive to the ambient temperature being lower than athird predefined threshold that is lower than the second predefinedthreshold.
 7. The method of claim 6 wherein the second blower motorvoltage range and the third blower motor voltage range have minimumvoltages generally corresponding to the first minimum voltage.